This invention is related to the field of metal cutting tools and, more specifically, to the field of milling cutters. Most specifically, this invention has application to a very special type of milling cutter especially useful in cutting sprockets.
As is known in the prior art, a sprocket cutter has a number of stations at which there are means for cutting the contour of a sprocket. The cutting means is typically a number of cutter buttons or round inserts with their cutting edges arranged in the shape of the sprocket contour. The inserts at each station are slightly displaced parallel to the axis of rotation from the inserts at every other station. In this way, a complete revolution will cause the entire sprocket contour to be contacted by the cutting edges of the inserts.
In the past, the inserts have been attached directly to the cutter body by means of screws or similar fastening means in conjunction with a hole in the center of the insert. See, for example, U.S. Pat. No. 3,540,103, A problem with this type of fastening means is that during use, the insert may wobble slightly, or even loosen, thereby causing loss of tolerance.
It is thus desirable to have an insert that will not loosen during use.
Another problem with the prior art is that, if the insert should break or become dislodged, the cutter body itself may be exposed to the workpiece. This can cause damage to the cutter body, a very expensive piece of equipment.
It is thus desirable to prevent damage to the cutter body.
Thus, it is an object of this invention to have a sprocket cutter in which the cutting inserts are rigidly held.
It is another object to have a sprocket cutter in which the inserts are resistant to loosing.
It is a further object to have a sprocket cutter in which the cutter body is prevented from damage due to a broken or dislodged cutting insert.
It is a still further object to have a sprocket cutter that will cut an accurate contour over long periods of use.